One vertex per element, one color per generator, with an edge from x to x·s.
(9,10)(11,18)(12,13)(14,15)(16,19)(17,22)(20,24)(21,23)(26,30)(31,34)(32,36)(38,40) involution — undirected(1,2)(3,7)(4,6)(5,8)(10,15)(11,19)(13,22)(20,23)(25,26,29,30)(27,31,33,34)(28,36,37,32)(35,40,39,38)(1,2,4,6)(3,5,8,7)(10,15)(12,17)(16,18)(20,23)(27,33)(31,34)(35,39)(38,40)(1,2,4,6)(3,5,8,7)(9,11,14,19)(10,16,15,18)(12,20,17,23)(13,21,22,24)(25,26)(27,34)(28,32)(29,30)(31,33)(35,40)(36,37)(38,39)(1,2)(3,5)(4,6)(7,8)(9,12,14,17)(10,13,15,22)(11,20,19,23)(16,21,18,24)(25,27,29,33)(26,31,30,34)(28,35,37,39)(32,38,36,40)(1,3)(2,5)(4,8)(6,7)(9,13)(10,17)(11,21)(12,15)(14,22)(16,23)(18,20)(19,24)(25,28)(26,32)(27,35)(29,37)(30,36)(31,38)(33,39)(34,40) involution — undirectedA Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.